Abstract

RODRIGUEZ, Diana Catalina; PENUELA, Gustavo  and  MORATO, Jordi. Evaluation of the biocidal potential of hydrogen peroxide and copper sulphate for biofilm removal in drinking water systems. Rev. P+L [online]. 2013, vol.8, n.1, pp.9-18. ISSN 1909-0455.

Abstract Introduction. The biofilms are communities of microorganisms which adhere to surfaces, thus avoiding the rapid and effective biocidal action and causing deterioration of the quality of the water in the distribution networks. Objective. To evaluate the efficiency of removal of biofilms in distribution networks of drinking water, as biocides using hydrogen peroxide and copper sulfate at different concentrations. Materials and methods. Biocides such as hydrogen peroxide (H₂O₂, 200 mg/L, 1000 mg/L and 12000 mg/L) and copper sulfate (CuSO₄, 0.2 mg/L, 0.6 mg/L and 1.0 mg/L) were used. They were applied to a pilot system used for the formation of biofilm in the distribution system of Medellin, Colombia. The time taken for the adhesion of microorganisms to the pilot was 20 days. Results. A biofilm removal of 99% was obtained, using a concentration of 12000 mg/L of H₂O₂ in a contact time of 60 minutes, consuming 27% of the initial H₂O₂. On the other hand, the use of CuSO₄ reached the maximum removal, 67%, using a concentration of 1.0 mg/L in a contact time of 60 minutes, consuming 41% of the initial CuSO₄ and evidencing the efficiency in the removal of hydrogen peroxide. Conclusion. The H₂O₂ has shown to be a biocide which acts strongly on the bacterial cells since in the three concentrations used it was observed a significant decrease in heterotrophic bacterial counts, compared with the three tested concentrations of CuSO₄.

Keywords : biofilm; biocide; hydrogen peroxide; copper sulfate; heterotrophic bacteria.

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